The owner of our property is a friend. The notice of Trustee's sale has been posted at our house. The bank also posted a notice that 2924.8 of California Civil code states we may have to enter into an agreement with the new owners or they may give us a 60 day eviction notice. But 2924.8 (c) states that this only applies if the billing address for the mortgage is different than the property address. I know that the owner gets mail for this loan at both his house and ours. How do I find out how long I will have before I have to move? The sale date is Dec 11. I have small children and do not want to be surprised, but Dec 11 is way too soon. HELP...

At the eviction hearing, you show owner does not live at that address, you should be given the 60 days.

Also you do not have to pay the friend any rent, and in fact in California the friend owes you any rent back during the period they were in foreclosure.
California has more protections than other states.

So after the auction, there should be an eviction notice posted? And who does that? Who can I complain to? Who sets up the eviction hearing?

The new owner does.

Under CA law, under certain conditions the landlord is required to apply rental payments towards the mortgage. Its possible your landlord comes under this law or may not depending on how long you hae rented and other circumstances.

Once the house is sold, a vacate notice will be posted. If you do not vacate by the deadline then eviction proceedings will be started.